Filed under Nutrition in Practice …

Aug 13 2010
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From the Source, Myth Buster, Nutrition in Practice

Omega-3s – The Verdict!

SPECIAL ISSUE: OMEGA-3 WEEK ON THE FODDER FILE

PART 4 OF 4: OMEGA-3 – THE VERDICT

It’s been an exciting week on the Fodder File.  I’ve learned a lot, and I hope you have too. So now it’s time for the Verdict!

This is basically where the evidence stands:

Heart Health:  Excellent. For people at high risk.

Brain Health: Very Good. For normal development of brain and eyes.  Sketchy for added benefits.

Planet Health: Strong. Omega-3 recommendations are detrimental to planet health.

It’s up to you… Based on what you have read, you decide:

You can review the Omega-3 posts by clicking on the icons below:

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Aug 12 2010
2 Comments
From the Source, Myth Buster, Nutrition in Practice

Omega-3s and Planet Health

SPECIAL ISSUE: OMEGA-3 WEEK ON THE FODDER FILE

PART 3 OF 4: PLANET HEALTH

Environmental sustainability is a big issue, and the field of nutrition and health should not be exempt from responsible practice.

With health benefits being significant for cardiovascular disease and possible in cognitive and visual performance, there is certainly evidence to support increasing intakes of fish for the long-chain omega-3 fats in some people.

However, 35% of the world’s fish stocks have collapsed, and we’ve plateaued  on how much fish we’re bringing in. If we are to take recommendations for health seriously, and every Canadian (North American? Human?) increased their intake of fish by 2-3 fold, the consequences would be catastrophic.

State of fish stocks. Taken from Jenkins et al.

So wild fish are out of the question.  What about farmed fish, you ask?

Well, aquaculture is primarily fixated on carnivorous fish like salmon and sea bass.  The diet for these fish?  Fishmeal and fish oils from smaller fish – the source of omega-3s.  It directly perpetuates the problem.  Check out this gem from Naylor et al.:

“It takes 2.5–5 kg of feed fish to make 1 kg of farmed carnivorous fish.”

In addition to the potential detrimental effects increased recommendations could have on the state of the worlds ocean critters, there are socio-economic and health concerns at the human level.  As Brunner notes:

“Overfishing undermines food security by reducing the supply of a vital source of dietary protein, particularly in the coastal regions of less economically developed countries. … These dynamics are likely to increase health inequalities within and between populations.”

But the main question that hasn’t been answered yet, is why we need to get omega-3 from fish at all?  Well, you’re right.  Omega-3 fats are found in many plant sources including flax, canola oil and soy beans.  But the critical thing is that not all omega-3s are equal.

Omega-3s are a family of fats, with short, medium and long-chain members.  Plants are rich in the medium-chain ALA omega-3.  But the health benefits that we see come from the long-chain DHA and EPA, which are only found in marine sources.

But there may be hope.  The long-chain DHA accumulates up the food chain in the ocean.  The primary producers of DHA are microalgae, consumed by krill (tiny crustaceans), then by larger and larger fish.  There are efforts underway to grow and purify DHA from algae, which would satisfy ethical (and vegetarian) demands.

Health recommendations have serious impacts on the planet.  We cannot neglect to consider this when wrapped-up in the righteous guise of human health.  After all, human health is planet health.  We cannot separate the two.

So what’s the take-home message?

Fish stocks are dwindling. Increasing recommendations for optimal heart and brain health would instantly outstrip the available supply of fatty fish, so we had better be damn sure that the science is solid if we’re going to go down that road (or river).  The old adage of being up a brown creek without a paddle comes to mind.  There may be other potential sources of the beneficial DHA in algae (but that’s missing the other heart-healthy long-chain omega-3, EPA).  This is going to be a tough call.

STAY TUNED FOR PART 4 OF 4 TOMORROW – THE VERDICT!

See PART 1 – HEART HEALTH HERE

See PART 2 – BRAIN HEALTH HERE

References after the jump. Continue reading →

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Aug 11 2010
2 Comments
From the Source, Myth Buster, Nutrition in Practice

Omega-3s for Brain Health

SPECIAL ISSUE: OMEGA-3 WEEK ON THE FODDER FILE (Rebroadcast)

PART 2 OF 4: BRAIN HEALTH

At the age of 20, the average male has got 175,000 km of myelinated neurons in his brain, enough to go around the world almost 4.5 times!  By the age of 80, that male will have lost almost half his myelinated neurons (92,700 km).

To be honest, I was very surprised when I read those facts.  But it serves to highlight the importance of caring for our brains.

Our brain is mostly fat – 60% actually.  And a major component necessary for proper brain development and function is the long-chain omega-3 fatty acid, docosahexaenoic acid, or DHA.  This is especially important during fetal and childhood brain development.

DHA is also essential for building rod cells in the retina (responsible for night-vision). It’s indispensable for normal function, but will we super-charge our brains and eyes with taking fish oil capsules?

Well, the data appears to have a checkered history.  I can’t list the whole body of literature here, but it’s less consistent than the heart-health data.  A couple of big reviews by the Cochrane Collaboration, the gold-standard for meta-analyses of multiple studies, found DHA-supplemented formulas didn’t do much for pre-term infants:

“no clear long-term benefits were demonstrated for infants receiving formula supplemented with [long-chain omega-3s].”

The story for infants born at term fed with DHA-supplemented formula is a little hazier:

“[Results] have not shown beneficial effects of [long-chain omega-3] supplementation of formula milk on the physical, visual and neurodevelopmental outcomes of infants born at term.”

However, it goes on to say that there are some conflicting results that show benefits of DHA-supplementation, which deserve more study.

Other recent research has shown that chidren with ADHD may benefit from fish-oil supplementation (~1g/day), and consumption of high amounts of fish could translate into better grades for kids (that from a Swedish study).  Hmmm…

On the other end of the age spectrum, patients with Alzheimers Disease are looking to long-chain omega-3s from marine sources for help.  But the scientific research is lacking.

Epidemiological studies (population-based) suggest that people who eat fish once-per week have a 60% reduced chance of developing Alzheimers:

“Participants who consumed fish once per week or more had 60% less risk of Alzheimer disease compared with those who rarely or never ate fish (relative risk, 0.4; 95% confidence interval, 0.2-0.9).”

Follow-up clinical trials have been a little more cryptic.  Fish/omega-3 intake appears to potentially play a protective effect if consumed regularly before advanced stages of Alzheimers, but once those advanced stages are reached, there’s no benefit.  More research needs to be done in this field in particular.

I can’t paint the whole picture here, but long-chain omega-3s from marine sources have also been implicated in playing a beneficial role in other mental conditions like major depression, psychosis, and anxiety disorders.

So what’s the take-home message?

Well, there is absolutely no doubt that we need DHA and other omega-3s (including shorter chain ALA, which can be converted to DHA in the body, though to a limited extent) for normal brain and eye health. Pregnant and lactating women might benefit their future child by taking an omega-3 capsule to boost DHA levels, but you should talk to your to doctor about this!  For the general population, taking a fish-oil supplement will not hurt (adverse reactions are limited to very high intakes of >3-4 g/day), and it might even benefit you in the long run when considering brain and neural conditions like Alzheimers.  There’s still a whack-load of more research that needs to be done to convince me of the miraculous brain-effects that omega-3s have been purported to play, but those might come in time.  I’m certainly open to it.

STAY TUNED FOR PART 3 OF 4 TOMORROW: OMEGA-3S AND PLANET HEALTH

SEE PART 1 (HEART HEALTH) HERE.

(Omega-3 Week originally broadcast in March 2010)

References after the jump.

Continue reading →

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Aug 10 2010
3 Comments
From the Source, Myth Buster, Nutrition in Practice

Omega-3s for Heart Health

SPECIAL ISSUE: OMEGA-3 WEEK ON THE FODDER FILE (Rebroadcast)

PART 1 OF 4: HEART HEALTH

Possibly the most convincing evidence for consuming DHA and EPA, Omega-3s from marine sources, has to do with the cardio-protective effects of these nutrients.

A paper published in the March issue of the American Journal of Clinical Nutrition, one of the most respected journals in the medical nutrition field, correlated biochemical markers of heart disease risk with intake of marine-based omega-3s (EPA and DHA) in Yup’ik Eskimos, a population with traditionally high intakes of fish.  The authors came to the conclusion that,

“Increasing EPA and DHA intakes to amounts well above those consumed by the general US population may have strong beneficial effects on chronic disease risk.”

We’re talking about big increases in intake.  Right now, Health Canada recommends eating fatty fish like salmon or mackerel 2 times per week. According to Dr. Bruce Holub, EPA/DHA Omega-3 expert, this number should be closer to 5-7 times per week if we’re going to hit the intakes needed to reduce chronic disease.  Or you could take 1-3 grams (1000-3000 mg) per day from capsules if you like.

What DHA and EPA (from marine sources) do do:

- substantially reduce fasting serum tri-glycerides (good)

- lower TG:HDL cholesterol ratio (good)

- increase LDL and total cholesterol (“bad”)

- lower blood viscosity, and platelet activation (good)

When we talk about mortality and morbidity numbers, a recent meta-analysis by Marik and Varon on DHA/EPA supplement trials found that,

“Dietary supplementation with omega-3 fatty acids significantly reduced the risk of cardiovascular deaths (OR: 0.87, 95% CI: 0.79–0.95, p = 0.002) and all-cause mortality (OR: 0.92,95% CI: 0.85–0.99, p = 0.02).”

These are statistically significant numbers, the measure for whether a treatment actually works.  In this case, DHA/EPA supplementation works.

Additional findings showed that in moderate-risk populations (high cholesterol, atherosclerosis), supplementation reduced the risk of non-fatal cardiovascular events (OR: 0.92, 95% CI: 0.85–0.99, p = 0.02).  The biggest benefits are seen in high-risk groups, or people who have already had a cardiovascular event like a heart attack.

A landmark study done in Italy, called the GISSI-Prevenzione Study, examined the effect of DHA/EPA supplementation in this high-risk population.  Their findings were huge: Statistically significant reductions in risk of sudden death (RR 0.47; 95% CI 0.219 to 0.995; P=0.048) and total mortality (RR 0.59; 95% CI 0.36 to 0.97; P=0.037).

The amazing thing about these results is that they were apparent at just 4 months after initiation of treatment (this is very quick), and that patients were taking conventional medications on top of the omega-3 supplement – and it was still safe and effective.  Awesome.

So what’s the take-home message?

Start now! If you have had a cardiovascular event such as a myocardial infarction (heart attack), or are at moderate risk (have high cholesterol – your doctor can check this), then you might benefit from taking a fish oil capsule containing at least 1 gram (1000 mg) of EPA+DHA (combined) from marine sources.  Print the GISSI-Prevenzione study (it’s free), and take it to your doctor to get his/her advice on whether you should take DHA and EPA.

STAY TUNED FOR PART 2 OF 4 TOMORROW – BRAIN HEALTH

(This post was originally posted on the Fodder File in March 2010)

References after the jump.

Continue reading →

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Jun 30 2010
2 Comments
From the Source, Nutrition in Practice

In one ear…

A useful starting point, but how do people understand and implement these recommendations? It gets tricky...

Health and dietary messages do not fall on deaf ears.

The results of a recent qualitative study from the UK illustrate that people are cognizant of health “slogans,” but that they get augmented when being put into action.

The authors explored the affect of dietary recommendations on the awareness and action of mother’s of a low socio-economic status.  It was a really fascinating study (with free full text) which provides evidence for something I have suspected for a long time:

People get the message. They’re familiar with the concept of eating plenty of fruits and vegetables, laying off the fast food and that a “poor diet” is a contributor to “poor health.” But there is something happening between hearing the message, and incorporating that into a pattern of their everyday life.

The authors commented:

“There are a number of reasons why people may not or cannot change their diet, including convenience, limited resources, and cooking skills.  An alternative explanation for poor uptake of dietary advice is that individuals themselves do not perceive their diet to be particularly unhealthy or at odds with official advice and therefore do not consider changing their diet.”

This is the kicker, and something fascinating that emerged with this study.  When mothers were interviewed, it became apparent that some of them did not see their (unhealthy) diet as “unhealthy,” something that was tied to their understanding of a “balanced diet”.

“This concept, according to official health promotion recommendations, involves a diet incorporating the major food groups and providing the body with the variety of nutrients needed for good health. Instead, the mothers’ interpretation incorporated the notion of balancing good food with bad food and was therefore very different from official definitions, although both definitions of balance (spread and equilibrium) could be valid.”

When asked what a good diet is, one subject replied:

“All the things that don’t taste so good, well, fresh things, fish, vegetables, fruit.”

Another went on:

“It’s a short life that we lead, and I think if you haven’t got a little of a vice in your life, it’s a bit boring, isn’t it? (Laughs) I mean, you know, you can’t be like, what’s the name, uhm, that woman on “You Are What You Eat” [a UK television program]. Blimey! I’d kill myself, I think, if I had to eat that diet all the time (laughs).”

I’m sure many of us can relate to this, but it really speaks to the challenge faced by health-care providers and dietitians.  I have listened to a physician advise her patient to “eat well and get plenty of exercise.”  The results from this study illustrate the futility of these simplistic recommendations.

How to effectively communicate the importance of a truly balanced diet is a trying task.  It is not just ensuring that patients (and the public) are aware of recommendation “catch terms”, but also the deeper dimension as to how those same patients understand health recommendations and are applying them in their lives.

After that, it is important to provide clear, detailed and realistic advice on positive dietary modification.

References after the jump.

Continue reading →

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